Spur-center.



PATENTED JUNE 23, 1908. J. E. DE MARBY.

SPUR CENTER.

APPLICATION FILED SBPT.16,1907.

2 SHEETS-SHEET 1.

JOSEPH E. DE MAREY, OF BRIDGEPORT, CONNECTICUT.

SPUR-CENTER.

Specification of Letters Patent.

Patented June 23, 1908.

Application filed September 16, 1907. Serial No. 393,100.

To all whom it may concern:

Be 1t known that I, JOSEPH E. DE MAREY,

a citizen of the United States, residing at.

Bridgeport, in the county of Fairfield and State of Connecticut, haveinvented certainv new and useful Improvements in Spur-Centers, of whichthe following is a specification.

This invention relates to lathes and more particularly to centerstherefor, and has for its object to provide a spur center arranged foruse in a chuck or in connection with a dog to hold a body to be turnedin fixed relation to the revoluble member or head of the lathe.

Another object is to rovide a spur center which will be extreme y simpleand which may thus be manufactured at a low figure.

Other objects and advantages will be apparent from the followingdescription, and it will be understood that changes in the specificstructure shown and described may be made within the scope of the claimswithout departing from the spirit of the invention.

In the drawings forming a portion of this specification, and in whichlike numerals of reference indicate similar parts in the severalviews,Figure 1 is a view showing a portion of a lathe in section, thepresent spur center being engaged in the chuck. Fig. 2 is a perspectiveview of the present center. Fig. 3 is a longitudinal view of the centertaken in sections. Fig. 4 is a detailed view showing the arrangement anduse of the tail piece.

Referring now to the drawings, the present spur center comprises a stem7, of cylindrical shape and carrying an enlarged angular head 8 at itsforward end. A longitudinal passage 9 is formed through the stem, and isextended through the head 8, this passage communicating centrally withan angular recess 10 formed in the forward space of the head.

The portion of the head 8 surrounding the central recess 10, is cut awayas shown at 11, to form a lurality of forwardly directed teeth, eachaving a straight face 13 and a slanted face 14, the straight faces beingturned in a common direction circumferentially of the head.

A center pin 15 is driven into the forward end of the passage 9, and hasits forward end sharpened as shown at 16, this center pin extendingforwardly beyond the free ends of the teeth 12 for engagement aconsiderable distance into a body to be turned, while the teeth 12 areembedded but slightly in the end of such a body, as shown in thedrawings. By reason of theformation of the recess 10,

.the center pin lies in spaced relation to the teeth 12, as shown.

It will of course be understood that the straight faces 13 of the teeth12 are turned in the direction of rotation of the lathe, so that thetendency is to hold these teeth in engagement with the body to beturned. Should they become firmly embedded in such body, it is onlynecessary to give the latter a turn in a direction with the straightfaces 13, when the slant of the faces 14 will cause the teeth todisengage themselves from the body.

The rearward end of the passage 9 is enlarged conically, as shown, theconical enlargement being indicated at 17. The enlargement is thusarranged to receive the forward extremity of a head center, as shown.

Recesses 18' are formed in the Wall of the conical enlargement 17, theserecesses being arranged to receive and hold a quantity of oil tolubricate the center so that the spur center may turn freely thereon,when it is desired to use the spur center u on the tail center, whichmay be done as wi 1 be readily understood.

In the last figure of the drawings, there is shown a tail piece of diskform, as indicated at A, provided with a central passage B and equippedwith a forwardly extending sharpened peripheral flange C. The rearwardportion of the passage B is enlarged conically similar to theenlargement of the passage 9 and is provided with oil receiving recessesD. It will be understood that the tail piece just described has itsperipheral flange engaged in the end of the body to be turned and thatit rests with the tail center of the lathe in the conical enlargement ofthe passage B.

What is claimed is: v 1. A center for lathes com rising a body portionhaving a passage formed therethrough, said passage having its rearwardend enlarged conically and provided with oil receiving recesses in itsinner surface.

2. A spur center comprising a stem, an anular head carried by the stem,a passage formed through the stem and head, a sharpened center pinengaged in the forward end of the passage, and forwardly extending teethcarried by the head and surrounding the pin.

3. A spur center comprising a stem, a head carried by the stem, saidhead and stem having a passage formed therethrough, said passage havingits rearward end enlarged conically, a plurality of forwardly extendingteeth carried by the head, and a center pin engaged in the forward endof the passage, said center pin extending forwardly beyond the 'teethand having said forwardly extending a passage formed therethroughcommunicating with the recess, said head having its peripheral portionscut away to form a p rality of forwardly extending teeth surrounding therectangular recess, and a center pin engaged in the forward end of thepassage and extending through the rectangular recess and projectingbeyond the teeth.

In testimony whereof I aflix my signature, in presence of two witnesses.

HENRY GREENSTEIN, JosEPH G. SHAPIRO.

